U.S. patent application number 11/789018 was filed with the patent office on 2008-10-23 for near infrared dyes.
Invention is credited to Sterling Chaffins, Cari L. Dorsh, Vladek Kasperchik, Vyacheslav Olkhovik, Andreii Pap, Dimitriy Vasilevskii.
Application Number | 20080262222 11/789018 |
Document ID | / |
Family ID | 39872913 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080262222 |
Kind Code |
A1 |
Kasperchik; Vladek ; et
al. |
October 23, 2008 |
Near infrared dyes
Abstract
Near infrared (NIR) dyes, image recording substrate including
the NIR dye, and methods of making the NIR dyes, are disclosed.
Inventors: |
Kasperchik; Vladek;
(Carvallis, OR) ; Olkhovik; Vyacheslav; (Minsk,
BY) ; Pap; Andreii; (Minsk, BY) ; Vasilevskii;
Dimitriy; (Minsk, BY) ; Dorsh; Cari L.;
(Corvallis, OR) ; Chaffins; Sterling; (Corvallis,
OR) |
Correspondence
Address: |
HEWLETT PACKARD COMPANY
P O BOX 272400, 3404 E. HARMONY ROAD, INTELLECTUAL PROPERTY ADMINISTRATION
FORT COLLINS
CO
80527-2400
US
|
Family ID: |
39872913 |
Appl. No.: |
11/789018 |
Filed: |
April 23, 2007 |
Current U.S.
Class: |
540/554 |
Current CPC
Class: |
C09B 23/0066 20130101;
C09B 57/10 20130101; C09B 47/045 20130101; B41M 5/465 20130101;
C09B 55/009 20130101 |
Class at
Publication: |
540/554 |
International
Class: |
C07D 259/00 20060101
C07D259/00 |
Claims
1. A near infrared (NIR) dye comprising: a silicon
2,3-naphthalocyanine derivative having the formula I: ##STR00005##
wherein R is selected from (CH.sub.2CH.sub.2O).sub.nR1,
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2, and combinations thereof;
wherein n is 2 to 20; wherein R1 is selected from a hydrocarbon
having 1 to 10 carbon atoms; wherein m is 1 to 15; wherein R2 is
selected from a hydrocarbon having from 1 to 10 carbon atoms;
wherein (CH.sub.2CH.sub.2O).sub.nR1 is selected from a linear
(CH.sub.2CH.sub.2O).sub.nR1 and a branched
(CH.sub.2CH.sub.2O).sub.nR1; and wherein
(CH.sub.2CH(CH.sub.3)O).sub.mR2 is selected from a linear
(CH.sub.2CH(CH.sub.3)O).sub.mR2 and a branched (CH.sub.2CH
(CH.sub.3)O).sub.mR2.
2. The NIR dye of claim 1, wherein the wherein n is 2 to 10;
wherein R1 is selected from a hydrocarbon having 1 to 5 carbon
atoms.
3. The NIR dye of claim 1, wherein m is 1 to 10, and wherein R2 is
selected from a hydrocarbon having from 1 to 5 carbon atoms.
4. The NIR dye of claim 1, wherein R is R1, and wherein R1 is a
group selected from: methyl, ethyl, propyl, iso-propyl, butyl,
iso-butyl, and tert-butyl.
5. The NIR dye of claim 4, wherein (CH.sub.2CH.sub.2O).sub.nR1 is a
linear (CH.sub.2CH.sub.2O).sub.nR1.
6. The NIR dye of claim 4, wherein (CH.sub.2CH.sub.2O).sub.nR1 is a
branched (CH.sub.2CH.sub.2O).sub.nR1.
7. The NIR dye of claim 1, wherein R is R2 and R2 is a group
selected from: methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl,
and tert-butyl.
8. The NIR dye of claim 7, wherein (CH.sub.2CH(CH.sub.3)O).sub.mR2
is a linear (CH.sub.2CH(CH.sub.3)O).sub.mR2.
9. The NIR dye of claim 7, wherein (CH.sub.2CH(CH.sub.3)O).sub.mR2
is a branched (CH.sub.2CH(CH.sub.3)O).sub.mR2.
10. The NIR dye of claim 9, wherein subscript m is 3 to 6 and R2 is
a butyl group.
11. An image recording substrate comprising: a matrix, a color
former, an activator, and a radiation-absorbing compound, wherein
the radiation-absorbing compound includes a near infrared dye
having formula I: ##STR00006## wherein R is selected from
(CH.sub.2CH.sub.2O).sub.nR1, (CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2,
and combinations thereof; wherein n is 2 to 20; wherein R1 is
selected from a hydrocarbon having 1 to 10 carbon atoms; wherein m
is 1 to 15; wherein R2 is selected from a hydrocarbon having from 1
to 10 carbon atoms; wherein (CH.sub.2CH.sub.2O).sub.nR1 is selected
from a linear (CH.sub.2CH.sub.2O).sub.nR1 and a branched
(CH.sub.2CH.sub.2O).sub.nR1; and wherein
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2 is selected from a linear
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2 and a branched
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2.
12. The image recording medium of claim 11, wherein the substrate
is selected from a paper medium, a transparency, a compact disk
(CD), and a digital video disk (DVD).
13. The image recording medium of claim 11, wherein the substrate
comprises an optical disk.
14. The image recording medium of claim 11, wherein
(CH.sub.2CH(CH.sub.3)O).sub.mR2 is a branched
(CH.sub.2CH(CH.sub.3)O).sub.mR2, and wherein subscript m is 3 to 6
and R2 is a butyl group.
15. A method for preparing a near infrared dye, the method
comprising: reacting 2,3-silicon naphthalocyanine dihydroxide with
a monoether compound selected from: monoethers of polyethylene
glycol, monoethers of polypropylene glycol, and monoethers of
1,2-propylene glycol in a solvent; producing the near infrared dye,
wherein the near infrared dye has formula I: ##STR00007## wherein R
is selected from (CH.sub.2CH.sub.2O).sub.nR1,
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2, and combinations thereof;
wherein n is 2 to 20; wherein R1 is selected from a hydrocarbon
having 1 to 10 carbon atoms; wherein m is 1 to 15; wherein R2 is
selected from a hydrocarbon having from 1 to 10 carbon atoms;
wherein (CH.sub.2CH.sub.2O).sub.nR1 is selected from a linear
(CH.sub.2CH.sub.2O).sub.nR1 and a branched
(CH.sub.2CH.sub.2O).sub.nR1; and wherein
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2 is selected from a linear
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2 and a branched
(CH.sub.2CH.sub.2(CH.sub.3)O).sub.mR2.
16. The method of claim 15, wherein (CH.sub.2CH(CH.sub.3)O).sub.mR2
is a branched (CH.sub.2CH(CH.sub.3)O).sub.mR2, and wherein
subscript m is 3 to 6 and R2 is a butyl group.
17. The method of claim 15, further comprising, applying the near
infrared dye to a substrate.
18. The method of claim 15, further comprising, applying the near
infrared dye to a paper medium.
19. The method of claim 15, further comprising, applying the near
infrared dye to a transparency.
20. The method of claim 17, further comprising, applying the near
infrared dye to an optical disk.
Description
BACKGROUND
[0001] In general, near infrared dyes do not have high extinction
in combination with good photostability. In addition, a few
available near infrared dyes with reasonable photostability
typically do not have good solubilities in UV-curable acrylate
monomers or in polymer coatings used for labeling optical storage
media. Lastly, vast majority near infrared dyes have pronounced
visible signatures, which add an unwanted color to the coating in
which it is used. Thus, there is a need to provide dyes that
overcome at least some the disadvantages or deficiencies of current
near infrared dyes.
SUMMARY
[0002] Briefly described, embodiments of this disclosure include
near infrared (NIR) dyes, image recording media including the NIR
dye, and methods of making the NIR dyes. One exemplary embodiment
of a NIR dye, among others, includes: a silicon
2,3-naphthalocyanine derivative having the formula I:
##STR00001##
wherein R is selected from (CH.sub.2CH.sub.2O).sub.nR1,
(CH.sub.2CH(CH.sub.3)O).sub.mR2, and combinations thereof; wherein
n is 2 to 20; wherein R1 is selected from a hydrocarbon having 1 to
10 carbon atoms; wherein m is 1 to 15; wherein R2 is selected from
a hydrocarbon having from 1 to 10 carbon atoms; wherein
(CH.sub.2CH.sub.2O).sub.nR1 is selected from a linear
(CH.sub.2CH.sub.2O).sub.nR1 and a branched
(CH.sub.2CH.sub.2O).sub.nR1; and wherein
(CH.sub.2CH(CH.sub.3)O).sub.mR2 is selected from a linear
(CH.sub.2CH(CH.sub.3)O).sub.mR2 and a branched
(CH.sub.2CH(CH.sub.3)O).sub.mR2.
[0003] One exemplary embodiment of image recording substrate, among
others, includes: a matrix, a color former, an activator, and a
radiation-absorbing compound, wherein the radiation-absorbing
compound includes a near infrared dye having formula I.
[0004] One exemplary embodiment of a method for preparing a near
infrared dye, among others, includes: reacting 2,3-silicon
naphthalocyanine dihydroxide with a monoether compound selected
from: monoethers of polyethylene glycol, monoethers of
polypropylene glycol, and monoethers of 1,2-propylene glycol in a
solvent and producing the near infrared dye, wherein the near
infrared dye has formula I.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Many aspects of this disclosure can be better understood
with reference to the following drawings. The components in the
drawings are not necessarily to scale. Moreover, in the drawings,
like reference numerals designate corresponding parts throughout
the several views.
[0006] FIG. 1 illustrates an embodiment of an imaging medium.
[0007] FIG. 2 illustrates a representative embodiment of a print
system.
DETAILED DESCRIPTION
[0008] Embodiments of the present disclosure will employ, unless
otherwise indicated, techniques of synthetic organic chemistry, ink
chemistry, media chemistry, and the like, that are within the skill
of the art. Such techniques are explained fully in the
literature.
[0009] The following examples are put forth so as to provide those
of ordinary skill in the art with a complete disclosure and
description of how to perform the methods and use the compositions
disclosed and claimed herein. Efforts have been made to ensure
accuracy with respect to numbers (e.g., amounts, temperature, etc.)
but some errors and deviations should be accounted for. Unless
indicated otherwise, parts are parts by weight, temperature is in
.degree. C., and pressure is at or near atmospheric. Standard
temperature and pressure are defined as 20.degree. C. and 1
atmosphere.
[0010] Before the embodiments of the present disclosure are
described in detail, it is to be understood that, unless otherwise
indicated, the present disclosure is not limited to particular
materials, reagents, reaction materials, manufacturing processes,
or the like, as such can vary. It is also to be understood that the
terminology used herein is for purposes of describing particular
embodiments only, and is not intended to be limiting. It is also
possible in the present disclosure that steps can be executed in
different sequence where this is logically possible.
[0011] It must be noted that, as used in the specification and the
appended claims, the singular forms "a," "an" and "the" include
plural referents unless the context clearly dictates otherwise.
Thus, for example, reference to "a support" includes a plurality of
supports. In this specification and in the claims that follow,
reference will be made to a number of terms that shall be defined
to have the following meanings unless a contrary intention is
apparent.
DISCUSSION
[0012] Near infrared (NIR) dyes, coating layers including the NIR
dyes, and substrates including coating layers are disclosed. In
particular, the NIR dyes can be used in laser imageable coatings,
as dyes for optical storage applications, and as dyes for
photodynamic therapy (e.g., cancer therapy).
[0013] The NIR dyes are advantageous because the NIR dyes of the
present disclosure have higher photostability relative to the
majority of currently used NIR dyes. In addition, NIR dyes of the
present disclosure have a low visible signature (i.e., low
extinction of the visible light) and a strong NIR extinction
compared to currently used NIR dyes. Furthermore, NIR dyes of the
present disclosure have good solubility in medium polarity solvents
and UV-curable monomers compared to majority of currently used NIR
dyes.
[0014] FIG. 1 illustrates an embodiment of an imaging medium 10.
The imaging medium 10 can include, but is not limited to, a
substrate 12 and a coating layer 14 (e.g., that includes a NIR
dye). The substrate 12 can be a substrate upon which it is
desirable to make a mark, such as, but not limited to, paper (e.g.,
labels, tickets, receipts, or stationery), overhead transparencies,
a metal/metal composite, glass, a ceramic, a polymer, and a
labeling medium (e.g., a compact disk (CD) (e.g., CD-R/RW/ROM) and
a digital video disk (DVD) (e.g., DVD-R/RW/ROM)).
[0015] In particular, the substrate 12 includes an "optical disk"
which is meant to encompass audio, video, multi-media, and/or
software disks that are machine readable in a CD and/or DVD drive,
or the like. Examples of optical disk formats include writeable,
recordable, and rewriteable disks such as DVD, DVD-R, DVD-RW,
DVD+R, DVD+RW, DVD-RAM, CD, CD-ROM, CD-R, CD-RW, DVD-HD, Blu-ray,
and the like. Other like formats can also be included, such as
similar formats and formats to be developed in the future.
[0016] The coating layer 14 can include, but is not limited to, the
matrix, the color former, the activator, the radiation-absorbing
compound (e.g., a NIR dye), as well as other components typically
found in the particular media to be produced.
[0017] The layer 14 may be applied to the substrate 12 via any
acceptable method, such as, but not limited to, rolling, spraying,
and screen-printing. In addition, one or more layers can be formed
between the layer 14 and the substrate 12 and/or one or more layer
can be formed on top of the coating layer 14. In one embodiment,
the layer 14 is part of a CD or a DVD.
[0018] To form a mark, radiation energy is directed imagewise at
one or more discrete areas of the layer 14 of the imaging medium
10. The form of radiation energy may vary depending upon the
equipment available, ambient conditions, the desired result, and
the like. The radiation energy can include, but is not limited to,
infrared (IR) radiation, ultraviolet (UV) radiation, x-rays, and
visible light. The radiation-absorbing compound (e.g., NIR dye in
the case of NIR imaging laser) absorbs the radiation energy and
heats the area of the layer 14 to which the radiation energy
impacts. The heat may cause the color former and the activator to
mix. The color former and the activator may then react to form a
mark (color) on certain areas of the layer 14.
[0019] FIG. 2 illustrates a representative embodiment of a print
system 20. The print system 20 can include, but is not limited to,
a computer control system 22, an irradiation system 24, and print
media 26 (e.g., imaging medium). The computer control system 22 is
operative to control the irradiation system 24 to cause marks
(e.g., printing of characters, symbols, photos, and the like) to be
formed on the print media 26. The irradiation system 24 can
include, but is not limited to, a laser system, UV energy system,
IR energy system, visible energy system, x-ray system, and other
systems that can produce radiation energy to cause a mark to be
formed on the layer 14. The print system 20 can include, but is not
limited to, a laser printer system and an ink-jet printer system.
In addition, the print system 20 can be incorporated into a digital
media system. For example, the print system 20 can be operated in a
digital media system to print labels (e.g., the layer is
incorporated into a label) onto digital media such as CDs and DVDs.
Furthermore, the print system 20 can be operated in a digital media
system to directly print onto the digital media (e.g., the layer is
incorporated the structure of the digital media).
[0020] As mentioned above, the coating layer includes, but is not
limited to, the matrix, the color former, the activator, and the
radiation-absorbing compound. In an embodiment, the radiation
absorbing compound is a NIR dye. The NIR dyes have a high (greater
than about 0.1.times.10.sup.5 ml*g.sup.-1*cm.sup.-1 or higher than
about 0.5.times.10.sup.5 ml*g.sup.-1*cm.sup.-1) molar extinction
from about 770 to 800 nm, while also having a narrow absorption
band (e.g., less than or equal to about 35 nm). In addition, the
NIR dyes have a low visible signature (extinction of NIR
peaks/extinction peaks in the visible range (about 400-700 nm)
greater than about 5 or greater than about 7). Furthermore, the NIR
dyes are soluble (e.g., greater than about 1 wt. % or greater than
about 2 weight % of the NIR dye) in UV curable monomers of acrylate
and/or methacrylate as well as other polymeriazable low molecular
species that can be used in radiation-curable coating formulations
(e.g., styrene and its derivatives). The UV curable monomers
include, but are not limited to, hexamethylene diacrylate,
tripropylene glycol diacrylate, lauryl acrylate, isobornyl
acrylate, isodecyl acrylate, neopentyl glycol diacrylate, isobornyl
acrylate, 2-phenoxyethyl acrylate, 2(2-ethoxy)ethylacrylate,
polyethylene glycol diacrylate and other acrylated polyols,
trimethylolpropane triacrylate, pentaerythritol tetraacrylate.
Additionally, the NIR dyes have a relatively high photostability
(i.e., lightfastness). For example, a dye dissolved in 7 .mu.m
thick acrylate coating results in loses less than about 50% of its
original extinction after being exposed to ambient light of typical
indoor intensity (about 400 Lux) for 90 days.
[0021] The NIR dyes include, but are not limited to, silicon
2,3-naphthalocyanines with medium polarity side chains (e.g.,
polyether side chains) attached to the central Si atom. Although
not intending to be bound by theory, these sidechains improve
solubility of the dye in medium polarity organic solvents such as
UV-curable acrylates and methacrylates comprising components of
majority modern UV-curable coating formulations. In an embodiment,
the NIR dyes can include compounds having formula I:
##STR00002##
[0022] R can include, but is not limited to,
(CH.sub.2CH.sub.2O).sub.nR1, (CH.sub.2CH (CH.sub.3)O).sub.mR2, and
combinations thereof. Subscript n can be 2 to 20, or 2 to 10R1 can
include a hydrocarbon having 1 to 10 carbon atoms, 1 to 5 carbon
atoms, and 1 to 4 carbon atoms. In particular, R1 can include, but
is not limited to, methyl, ethyl, propyl, iso-propyl, butyl,
iso-butyl, and tert-butyl. In addition, (CH.sub.2CH.sub.2O).sub.nR1
can be a linear (CH.sub.2CH.sub.2O).sub.nR1 and/or a branched
(CH.sub.2CH.sub.2O).sub.nR1. In particular,
(CH.sub.2CH.sub.2O).sub.nR1 is a branched
(CH.sub.2CH.sub.2O).sub.nR1, where the branching occurs at the end
hydrocarbon and not in the alkoxy chain itself.
[0023] Subscript m can be 1 to 15 or 1 to 10. In particular,
subscript m is 2 to 8. R2 can include a hydrocarbon having 1 to 10
carbon atoms and 1 to 5 carbon atoms. In particular, R2 can
include, but is not limited to, methyl, ethyl, propyl, iso-propyl
butyl, iso-butyl, and tert-butyl. In addition,
(CH.sub.2CH(CH.sub.3)O).sub.mR2 can be a linear
(CH.sub.2CH(CH.sub.3)O).sub.mR2 and/or a branched
(CH.sub.2CH(CH.sub.3)O).sub.mR2. In particular,
(CH.sub.2CH(CH.sub.3)O).sub.mR2 is a branched
(CH.sub.2CH(CH.sub.3)O).sub.mR2.
[0024] The NIR dye can be about 0.1 wt % to 5 wt % of the coating
layer, about 0.2 wt % to 3 wt % of the coating layer, and about 0.3
wt % to 2 wt % of the coating layer.
[0025] In general, the NIR dyes can be prepared by direct reaction
of 2,3-silicon naphthalocyanine dihydroxide (2,3-NC--Si(OH).sub.2)
with monoethers of polyethylene glycol and polypropylene glycol and
preferably that of 1,2-propylene glycol in a solvent such as in
mesitylene.
[0026] In an embodiment, the NIR dye is a compound having formula 1
where R equal to (CH.sub.2CH(CH.sub.3)O).sub.mR2. Subscript m is 3
to 6 and R2 is butyl group. In practice
(CH.sub.2CH(CH.sub.3)O).sub.mR2 is a mixture of oligomers, where m
is 3 to 6 with an average value between 4 and 5. In addition,
(CH.sub.2CH(CH.sub.3)O).sub.mR2 is branched. The NIR dye has a
molar extinction of about 397K I mol.sup.-1 cm.sup.-1 at about 773
nm, while also having a narrow absorption band of about 765 to 785
nm. In addition, the NIR dye has a low (highest extinction in
visible range 0.25.times.10.sup.5 ml*g.sup.-1*cm.sup.-1 at about
685 nm) visible signature (e.g., low absorption from about 400 to
700 nm). Furthermore, the NIR dye has a solubility of not lower
than 2 weight % of the dye) in 1,6-hexanediol diacrylate.
Additionally, the NIR dye has a relatively high photostability
(i.e., lightfastness). The coating based on a 50/50 mixture of
1,6-hexanedioldiacrylate and isobornyl acrylate containing 1 wt. %
of the dye showed a lower than 30% loss of extinction when being
exposed to fluorescent light of 400 Lux intensity for 90 days.
[0027] The NIR dye was prepared through direct reaction of silicon
2,3-naphthalocyanine dihydroxide (Si-2,3-NC(OH).sub.2) with
poly(propylene glycol)butyl ether having average Mn of about 340 in
mesitylene as the reaction environment. The reaction yield was
about 75%. The resulting dye had high molar extinction (about
397,790 I*mol.sup.-1 cm.sup.-1) comparable to that of
bis(trihexylsiloxy)silicon 2,3-naphthalocyanine (about 500,000
I*mol.sup.-1 cm.sup.-1). In addition, the NIR dye also had a
solubility in UV-curable acrylates (greater than about 2 wt. %) in
1,6-hexanediol diacrylate (SR238).
[0028] When being dissolved in UV-curable coatings dye showed
significant photostability. For example, with a load of about 1 wt.
% of dissolved NIR dye into the UV-curable coating based on 50/50
mixture of 1,6-hexanediol diacrylate and isobornyl acrylate. After
being screen-printed onto CD surface at thickness about 7 .mu.m the
coating had light-greenish coloration. After about 72 hrs exposure
of the coating to high intensity fluorescent light (21kLux), the
layer did not change significantly in coloration, which is a direct
indication of the dye photostability.
[0029] It should be noted that the NIR dyes are described in
conjunction with a coating layer for illustrative purposes only. As
such, the NIR dyes can be used individually or in combination with
other technologies such as, but not limited to, data recording dyes
in optical storage applications, and photodynamic therapy.
[0030] The matrix can include compounds capable of and suitable for
dissolving and/or dispersing the radiation absorbing compound, the
activator, and/or the color former. The matrix can include, but is
not limited to, UV curable monomers, oligomers, and pre-polymers
(e.g., acrylate derivatives. Illustrative examples of UV-curable
monomers, oligomers, and pre-polymers (that may be mixed to form a
suitable UV-curable matrix) can include but are not limited to,
hexamethylene diacrylate, tripropylene glycol diacrylate, lauryl
acrylate, isodecyl acrylate, neopentyl glycol diacrylate,
2-phenoxyethyl acrylate, 2(2-ethoxy)ethylacrylate, polyethylene
glycol diacrylate and other acrylated polyols, trimethylolpropane
triacrylate, pentaerythritol tetraacrylate, ethoxylated bisphenol A
diacrylate, acrylic oligomers with epoxy functionality, and the
like.
[0031] In an embodiment the matrix is used in combination with a
photo package. A photo package may include, but is not limited to,
a light absorbing species, which initiates reactions for curing of
a matrix such as, by way of example, benzophenone derivatives.
Other examples of photoinitiators for free radical polymerization
monomers and pre-polymers include, but are not limited to,
thioxanethone derivatives, anthraquinone derivatives, acetophenones
and benzoine ether types, and the like.
[0032] It may be desirable to choose a matrix that is cured by a
form of radiation other than the type of radiation that causes a
color change. Matrices based on cationic polymerization resins may
include photo-initiators based on aromatic diazonium salts,
aromatic halonium salts, aromatic sulfonium salts and metallocene
compounds, for example. An example of a matrix may include Nor-Cote
CDG000. Other acceptable matrices may include, but is not limited
to, acrylated polyester oligomers (e.g., CN293 and CN294, available
from Sartomer Co.).
[0033] The matrix compound is about 2 wt % to 98 wt % of the
coating layer and about 20 wt % to 90 wt % of the coating
layer.
[0034] As mentioned above, color formers can be included in the
coating layer. The color formers can include, but are not limited
to, leuco dyes and phthalide color formers (e.g., fluoran leuco
dyes and phthalide color formers as described in "The Chemistry and
Applications of Leuco Dyes", Muthyala, Ramiah, ed., Plenum Press
(1997) (ISBN 0-306-45459-9), which is incorporated herein by
reference).
[0035] The color forming composition can include, but is not
limited to, a wide variety of leuco dyes. Suitable leuco dyes
include, but are not limited to, fluorans, phthalides,
amino-triarylmethanes, aminoxanthenes, aminothioxanthenes,
amino-9,10-dihydro-acridines, aminophenoxazines,
aminophenothiazines, aminodihydro-phenazines,
aminodiphenylmethanes, aminohydrocinnamic acids (cyanoethanes,
leuco methines) and corresponding esters,
2(p-hydroxyphenyl)-4,5-diphenylimidazoles, indanones, leuco
indamines, hydrozines, leuco indigoid dyes,
amino-2,3-dihydroanthraquinon-es, tetrahalo-p,p'-biphenols,
2(p-hydroxyphenyl)-4,5-diphenylimidazoles, phenethylanilines,
phthalocyanine precursors (such as those available from Sitaram
Chemicals, India), and other known leuco dye compositions.
Experimental testing has shown that fluoran based dyes are one
class of leuco dyes which exhibit particularly desirable
properties.
[0036] In one aspect of the present disclosure, the leuco dye can
be a fluoran, phthalide, aminotriarylmethane, or mixture thereof.
Several non-limiting examples of suitable fluoran based leuco dyes
include 3-diethylamino-6-methyl-7-anilinofluorane,
3-(N-ethyl-p-toluidino)-6-meth-yl-7-anilinofluorane,
3-(N-ethyl-N-isoamylamino)-6-methyl-7-anilinofluoran-e,
3-diethylamino-6-methyl-7-(o,p-dimethylanilino)fluorane,
3-pyrrolidino-6-methyl-7-anilinofluorane,
3-piperidino-6-methyl-7-anilino-fluorane,
3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluorane,
3-diethylamino-7-(m-trifluoromethylanilino)fluorane,
3-dibutylamino-6-methyl-7-anilinofluorane,
3-diethylamino-6-chloro-7-anil-inofluorane,
3-dibutylamino-7-(o-chloroanilino)fluorane,
3-diethylamino-7-(o-chloroanilino)fluorane,
3-di-n-pentylamino-6-methyl-7-anilinofluoran,
3-di-n-butylamino-6-methyl-7-anilinofluoran,
3-(n-ethyl-n-isopentylamino)-6-methyl-7-anilinofluoran,
3-pyrrolidino-6-methyl-7-anilinofluoran,
1(3H)-isobenzofuranone,4,5,6,7-t-etrachloro-3,3-bis[2-[4-(dimethylamino)p-
henyl]-2-(4-methoxyphenyl)ethenyl]-,
2-anilino-3-methyl-6-(N-ethyl-N-isoamylamino)fluorane (S-205
available from Nagase Co., Ltd), and mixtures thereof.
[0037] Suitable aminotriarylmethane leuco dyes can also be used in
embodiments of the preset disclosure, such as
tris(N,N-dimethylaminophenyl)methane (LCV),
tris(N,N-diethylaminophenyl)methane (LECV),
tris(N,N-di-n-propylaminophenyl)methane (LPCV),
tris(N,N-di-n-butylaminophenyl)methane (LBCV),
bis(4-diethylaminophenyl)-(4-diethylamino-2-methyl-phenyl)methane
(LV-1),
bis(4-diethylamino-2-methylphenyl)-(4-diethylamino-phenyl)methane
(LV-2), tris(4-diethylamino-2-methylphenyl)methane (LV-3),
bis(4-diethylamino-2-methylphenyl)(3,4-dimethoxy-phenyl)methane
(LB-8), aminotriarylmethane leuco dyes having different alkyl
substituents bonded to the amino moieties wherein each alkyl group
is independently selected from C1-C4 alkyl, and aminotriaryl
methane leuco dyes with any of the preceding named structures that
are further substituted with one or more alkyl groups on the aryl
rings wherein the latter alkyl groups are independently selected
from C1-C3 alkyl. Other leuco dyes can also be used in connection
with the present invention and are known to those skilled in the
art. A more detailed discussion of some of these types of leuco
dyes may be found in U.S. Pat. Nos. 3,658,543 and 6,251,571, each
of which are hereby incorporated by reference in their entireties.
Additional examples and methods of forming such compounds can be
found in Chemistry and Applications of Leuco Dyes, Muthyala,
Ramaiha, ed., Plenum Press, New York, London, ISBN: 0-306-45459-9,
which is hereby incorporated by reference.
[0038] The color former can be about 3 wt % to 35 wt % of the
coating layer, about 10 wt % to 30 wt % of the coating layer, and
about 10 wt % to 20 wt % of the coating layer.
[0039] In addition to the NIR dye, the coating layer may include
additional radiation absorbing compounds. The additional radiation
absorbing compounds readily absorb a desired specific wavelength of
the marking radiation. The radiation absorbing compound may be a
material that effectively absorbs the type of energy to be applied
to the print substrate 16 to effect a mark or color change. The
radiation absorbing compound can include, but is not limited to,
IR780 (Aldrich 42,531-1) (1) (3H-Indolium,
2-[2-[2-chloro-3-[(1,3-dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)e-
thylidene]-1-cyclohexen-1-yl]ethenyl]-3,3-dimethyl-1-propyl-,
iodide (9Cl)); IR783 (Aldrich 54,329-2) (2)
(2-[2-[2-Chloro-3-[2-[1,3-dihydro-3,3-dimethyl-1-(4-sulfobutyl)-2H-indol--
2-ylidene]-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-3,3-dimethyl-1-(4-sulfo-
butyl)-3H-indolium hydroxide, inner salt sodium salt); Syntec 9/1
(3)); Syntec 9/3 (4); or metal complexes (e.g., dithiolane metal
complexes (5) and indoaniline metal complexes (6)).
##STR00003##
where M.sub.1 is a transition metal, R.sub.1, R.sub.2, R.sub.3, and
R.sub.4 are alkyl or aryl groups with or without halo substituents,
and A.sub.1, A.sub.2, A.sub.3, and A.sub.4 can be S, NH, or Se;
##STR00004##
where M.sub.2 is Ni or Cu and R.sub.5 and R.sub.6 are aryl or alkyl
groups with or without halo substituents.
[0040] Additional examples of radiation absorbing compounds can be
found in "Infrared Absorbing Dyes", Matsuoka, Masaru, ed., Plenum
Press (1990) (ISBN 0-306-43478-4) and "Near-infrared Dyes for High
Technology Applications", Daehne, S.; Resch-Genger, U.; Wolfbeis,
O., Ed., Kluwer Academic Publishers (ISBN 0-7923-5101-0), both
incorporated herein by reference.
[0041] The radiation absorbing compound can be about 0.2 wt % to 5
wt % of the coating layer, about 0.2 wt % to 2 wt % of the coating
layer, and about 0.2 wt % to 0.6 wt % of the coating layer.
[0042] As used herein, the term "activator" is a substance that
reacts with a color former, causing the color former to alter its
chemical structure and change or acquire color.
[0043] The activator can include a compound that has an acid such
as, but not limited to, a Lewis acid, has a functionality such as a
complexed transition metal, metal salt, phenolic compound, and
combinations thereof, and can be reactive with leuco dyes with or
without introduction of energy in the form of light and/or
heat.
[0044] In one embodiment, the activator can be a metal salt of an
aromatic carboxylic acid. The metal of the metal salt can include,
but is not limited to, transition metals such as zinc, tin, nickel,
iron, and other transition metals. In one embodiment, the metal
salt activator can be a zinc salt of an aromatic carboxylic acid.
Other metal salt activators include zinc salicylate, tin
salicylate, zinc 2-hydroxy naphthoate, 3,5-di-.alpha.-methylbenzyl
zinc salicylate, metal salts of rhodanate, xanthate, aluminate,
titanate, and zirconate, and mixtures thereof.
[0045] The activator can include, but is not limited to, a phenolic
resin, zinc chloride bisphenol, hydroxybenzoate, amidophenol,
anilides with hydroxyl groups, and benzoamides with hydroxyl groups
including N-(4-Hydroxyphenyl)acetamide, 2-acetamidophenol,
3-acetamidophenol, salicylanilide, p-hydroxybenzamide,
p-hydroxyphenyl acetamide, 3-hydroxy-2-napthanilide,
o-hydroxybenzanilide, 4-hydroxyphenyl sulfone,
2,4'-dihydroxydiphenyl sulfone,
Bis(4-hydroxy-3-allylphenyl)sulfone, 2,2',5,5'-Tetrahydroxy
diphenyl sulfone, 4-hydroxyphenyl-4'-isopropoxyphenly sulfone,
2,2-Bis(4-hydroxyphenyl)propane, and combinations thereof.
[0046] The activator can be about 2 wt % to 20 wt % of the coating
layer, about 2 wt % to 15 wt % of the coating layer, and about 2 wt
% to 10 wt % of the coating layer.
[0047] The crosslinking agent can include, but is not limited to,
aldehyde compounds (e.g., formaldehyde, glyoxal and
glutaraldehyde); ketone compounds (e.g., diacetyl and
cyclopentanedione); active halogen compounds (e.g.,
bis(2-chloroethylurea)-2-hydroxy-4,6-dichloro-1,3,5-triazine and
2,4-dichloro-6-s-triazine sodium salt); active vinyl compounds
(e.g., divinyl sulfonic acid, 1,3-vinylsulfonyl-2-propanol,
N,N'-ethylene-bis(vinylsulfonylacetamide), and
1,3,5-triacryloyl-hexahydr-o-s-triazine); N-methylol compounds
(e.g., dimethylolurea and methyloldimethylhydantoin); melamine
resins (e.g., methylolmelamine and alkylated methylolmelamine);
epoxy resins; isocyanate compounds (e.g.,
1,6-hexamethylenediisocyanate); aziridine compounds disclosed in
U.S. Pat. Nos. 3,017,280 and 2,983,611; carboxyimide compounds
disclosed in U.S. Pat. No. 3,100,704 which are incorporated herein
by reference; epoxy compounds (e.g., glycerol triglycidyl ether);
ethyleneimino compounds (e.g.,
1,6-hexamethylene-N,N'-bis-ethyleneurea); halogenated
carboxyaldehyde compounds (e.g., mucochloric acid and
mucophenoxychloric acid); dioxane compounds (e.g.,
2,3-dihydroxydioxane); metal-containing compounds (e.g., titanium
lactate, aluminum sulfate, chromium alum, potassium alum, zirconyl
acetate and chromiumacetate); polyamine compounds (e.g.,
tetraethylenepentamine); hydrazide compounds (e.g., adipic
dihydrazide); and low molecular weight compounds and polymers
having 2 or more oxazoline groups.
[0048] The crosslinking agent can be about 0.5 wt % to 2 wt % of
the coating coating layer, about 0.2 wt % to 1 wt % of the coating
layer, and about 0.2 wt % to 0.75 wt % of the coating layer.
[0049] Surfactants can also be present, such as alkyl polyethylene
oxides, alkyl phenyl polyethylene oxides, polyethylene oxide (PEO)
block copolymers, acetylenic PEO, PEO esters, PEO amines, PEO
amides, and dimethicone copolyols. If used, such surfactants can be
about 0.5 wt % to 5 wt % of the coating layer, about 0.5 wt % to
2.5 wt % of the coating layer, and about 0.5 wt % to 1 wt % of the
coating layer.
[0050] While embodiments of the present disclosure are described in
connection with the Examples and the corresponding text and
figures, there is no intent to limit the disclosure to the
embodiments in these descriptions. On the contrary, the intent is
to cover all alternatives, modifications, and equivalents included
within the spirit and scope of embodiments of the present
disclosure.
EXAMPLE 1
Preparation of 2,3-NC--Si Radiation Absorber:
[0051] About 2.32 g of NcSi(OH).sub.2 (2,97 mmol) was boiled in
about 300 ml mesitylene with a water trap over 3 hours. The
solution of poly(propylene glycol)butyl ether with an average
M.sub.n of about 340 (20 g, 58,8 mmol, Aldrich N 438103) in
mesitylene (20 ml) was added and the mixture was refluxed for 24
hours. Then, the reaction mixture was cooled, unreacted
NcSi(OH).sub.2 (800 mg) was filtered off and the filtrate was
concentrated in vacuum. The residue was dissolved in ethanol and
precipitated with water. The formed precipitate was filtered off,
washed three times with 70% ethanol, and dried. Chromatographic
separation on a short column with SiO.sub.2 gave 2.2 g of compound
Nc237 (about 75%). The dye Nc237 is a mixture about 6 main
compounds with R.sub.f 0,2-0,5 (EtOAc:toluene=1:5).
Preparation of Laser-Imageable Coating:
[0052] The image recording coating can be prepared by dissolving
the Bisphenol S in the UV-curable monomer mix to form a first
solution. Then, the other soluble components (e.g., Nc237, D8, SDP,
Pergafast-201, and Irgacure-1300) are dissolved in the mixture.
Subsequently, Foamblast-20F is added to the mixture. Finely-milled
BK400 leuco-dye and YKR-5010 are dispersed in the mixture (using
3-roll milling).
TABLE-US-00001 wt % Coating with improved photostability/marking
sensitivity UV-curable monomer mix 50% BK400 Leuco-dye (milled down
to 0.3 0.4 .mu.m) 25% Nc237 radiation absorber 1% (prepared as
described above) 4-Hydroxy-4'-isopropoxydiphenyl sulfone (D8) 6%
(phenolic developer) Bisphenol S (phenolic developer) 4%
Irgacure-1300 (photoinitiator) 6.5% Pergafast-201 (sulfonylurea
developer) 4% Foamblast-20F 2% YKR-5010 stable NIR pigment 1.5%
Total 100% UV-curable monomer mix SR238 25% SR506 35% Ebecryl-605
26% SR306HP 14% Total 100%
[0053] It should be noted that ratios, concentrations, amounts, and
other numerical data may be expressed herein in a range format. It
is to be understood that such a range format is used for
convenience and brevity, and thus, should be interpreted in a
flexible manner to include not only the numerical values explicitly
recited as the limits of the range, but also to include all the
individual numerical values or sub-ranges encompassed within that
range as if each numerical value and sub-range is explicitly
recited. To illustrate, a concentration range of "about 0.1% to
about 5%" should be interpreted to include not only the explicitly
recited concentration of about 0.1 wt % to about 5 wt %, but also
include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and
the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the
indicated range. The term "about" can include .+-.1%, .+-.2%,
.+-.3%, .+-.4%, .+-.5%, .+-.6%, .+-.7%, .+-.8%, .+-.9%, or .+-.10%,
or more of the numerical value(s) being modified. In addition, the
phrase "about `x` to `y`" includes "about `x` to about `y`".
[0054] Many variations and modifications may be made to the
above-described embodiments. All such modifications and variations
are intended to be included herein within the scope of this
disclosure and protected by the following claims.
* * * * *